Lamps, such as those used in projectors, may include a reflector to reflect and direct light. In some lamps, the reflector may include a dielectric interference coating that is deposited upon an underlying layer that is formed by spraying or dipping. Because the underlying layer is formed from spraying or dipping, available materials for the underlying layer are limited. In addition, with spraying or dipping, it is difficult to achieve a uniform surface thickness. The surface irregularities of the underlying layer that may result from spraying or dipping may impair performance of the reflector.